Semiconductor device and method for producing semiconductor device

ABSTRACT

A semiconductor device includes a semiconductor element, leads, and an encapsulation resin covering a portion of each of the leads and the semiconductor element. Each of the leads includes an external connection portion projecting from a side surface of the encapsulation resin. The external connection portion of at least one of the leads has opposite ends in a width-wise direction that extends along the side surface of the encapsulation resin. The external connection portion includes two recesses arranged toward a center in the width-wise direction from the opposite ends. The two recesses extend from a distal surface toward the encapsulation resin. The opposite ends in the width-wise direction define an end connection part. The external connection portion includes a part between the two recesses defining a center connection part.

BACKGROUND OF INVENTION

The present invention relates to a semiconductor device and a method forproducing a semiconductor device.

When a typical semiconductor device includes a semiconductor elementsuch as a transistor or a diode, the semiconductor device includes alead connected to the semiconductor element and an encapsulation resinencapsulating the semiconductor element (refer to, for example, JapaneseLaid-Open Patent Publication No. 2009-71033). The lead of thesemiconductor device is connected to, for example, a pad of a circuitboard by solder.

When a semiconductor device is mounted on a circuit board, solder may beinsufficient to connect a lead of the semiconductor device to a pad ofthe circuit board. Insufficient solder may result in an insufficientstrength to mount the semiconductor device.

SUMMARY OF INVENTION

It is an object of the present invention to improve the mount strength.

One aspect of the present disclosure is a semiconductor device thatincludes a semiconductor element, leads, and an encapsulation resincovering a portion of each of the leads and the semiconductor element.Each of the leads includes an external connection portion projectingfrom a side surface of the encapsulation resin. The external connectionportion of at least one of the leads has opposite ends in a width-wisedirection that extends along the side surface of the encapsulationresin. The external connection portion includes two recesses arrangedtoward a center in the width-wise direction from the opposite ends. Thetwo recesses extend from a distal surface of the external connectionportion toward the encapsulation resin. The opposite ends in thewidth-wise direction define an end connection part. The externalconnection portion includes a part between the two recesses defining acenter connection part.

Another aspect of the present disclosure is a method for producing asemiconductor device that encapsulates a semiconductor element and aportion of each of leads with a resin. The method includes steps ofpreparing a lead frame that form the leads, forming an encapsulationresin covering a portion of each of the leads and a semiconductorelement mounted on the lead frame, and forming an external connectionportion that projects from a side surface of the encapsulation resin bycutting the leads. The leads are connected to a frame portion of thelead frame by a frame connector that forms the external connectionportion. The frame connector includes a first through hole extending ina width-wise direction and second through holes extending from oppositeends of the first through hole away from the frame portion. In theforming an external connection portion, the frame connector is cutacross the first through hole so that the external connection portion isformed to have opposite ends in a width-wise direction that extendsalong a side surface of the encapsulation resin and include tworecesses. The two recesses are arranged toward a center in thewidth-wise direction from the opposite ends and extend from a distalsurface of the external connection portion toward the encapsulationresin. The opposite ends of the external connection portion in thewidth-wise direction define an end connection part. The externalconnection portion includes a part between the two recesses defining acenter connection part.

Another aspect of the present disclosure is a semiconductor device thatincludes a first lead including a die pad and an external connectionportion, a second lead including an internal connection portion and anexternal connection portion, a semiconductor element mounted on the diepad, and a connection plate electrically connecting the semiconductorelement and the second lead. The connection plate includes an elementconnector connected to the semiconductor element, a lead connectorconnected to the second lead, and a joint joining the element connectorand the lead connector. The second lead includes a restriction portionconnected to the lead connector and including restriction surfaces. Therestriction portion restricts movement of the connection plate with therestriction surfaces.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan view of a semiconductor device.

FIG. 2 is a schematic side view of the semiconductor device.

FIG. 3 is a schematic bottom view of the semiconductor device.

FIG. 4 is a partially perspective view of the semiconductor deviceshowing a lead.

FIG. 5 is a plan view showing an internal structure of the semiconductordevice.

FIG. 6 is a side view showing an internal structure of the semiconductordevice.

FIG. 7 is a cross-sectional view showing connection of a lead and aclip.

FIG. 8 is a partially enlarged view showing connection of asemiconductor element and a clip.

FIG. 9 is a partially plan view of a lead frame including leads.

FIG. 10 is a partially plan view of a lead frame including a clip.

FIG. 11 is a partially perspective view of a semiconductor deviceshowing a state of a first referential example of a lead.

FIG. 12 is a partially perspective view of a semiconductor deviceshowing a state of a second referential example of a lead.

FIG. 13 is a partially perspective view of a semiconductor deviceshowing a state of an embodiment of a lead.

FIG. 14 is a perspective view showing a mount state of the lead of thefirst referential example.

FIG. 15 is a perspective view showing a mount state of the lead of thesecond referential example.

FIG. 16A is a perspective view showing a mount state of the lead of theembodiment.

FIG. 16B is a cross-sectional view showing a mount state of the lead ofthe embodiment.

FIG. 17A is perspective view showing a mount state of the lead of theembodiment.

FIG. 17B is a cross-sectional view showing a mount state of the lead ofthe embodiment.

FIG. 18 is a schematic side view showing a modified example of asemiconductor device.

FIG. 19 is a schematic side view showing a modified example of asemiconductor device.

FIG. 20 is a schematic plan view showing a modified example of asemiconductor device.

FIG. 21 is a schematic plan view showing a modified example of asemiconductor device.

FIG. 22 is a schematic plan view showing a modified example of asemiconductor device.

FIG. 23 is a schematic plan view showing a modified example of asemiconductor device.

FIG. 24 is a partially plan view of a lead frame including a lead of thesemiconductor device shown in FIG. 23.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Each embodiment will now be described.

Elements in the drawings may be partially enlarged for simplicity andclarity and thus have not necessarily been drawn to scale. For the sakeof clarity, hatching lines may not be shown in the cross-sectionaldrawings.

As shown in FIGS. 1, 2, and 3, a semiconductor device 1 is shaped as arectangular plate.

The semiconductor device 1 includes a first lead 10, a second lead 20, asemiconductor element 30, a connection plate 40 (clip), and anencapsulation resin 50. The semiconductor device 1 of the presentembodiment includes multiple (two in FIG. 1) second leads 20.

The semiconductor element 30 is mounted on the upper surface of thefirst lead 10. The semiconductor element 30 is, for example, a diode andhas an upper surface and a lower surface, each of which includes anelectrode. The electrode arranged on the lower surface of thesemiconductor element 30 is electrically connected to the upper surfaceof the first lead 10 by solder 71 (refer to FIGS. 6 and 8), which willbe described later. The electrode arranged on the upper surface of thesemiconductor element 30 is electrically connected to the second leads20 by the clip 40. Portions of the first lead 10 and the second leads20, the semiconductor element 30, and the clip 40 are covered with theencapsulation resin 50.

The encapsulation resin 50 is shaped as a rectangular plate. Thematerial of the encapsulation resin 50 may be an insulative resin, forexample, an epoxy resin.

As shown in FIG. 2, the encapsulation resin 50 includes an upper surface51 and a lower surface 52. The lower surface 52 is opposed to a circuitboard when mounted. As shown in FIG. 3, the first lead 10 and the secondleads 20 are exposed from the lower surface 52 of the encapsulationresin 50. The first lead 10 and the second leads 20 each have a surfaceexposed from the encapsulation resin 50 defining a mount surface. Whenmounted on the circuit board, the mount surface is electricallyconnected to a pad of the circuit board by solder.

As shown in FIG. 1, the encapsulation resin 50 has a side surface 53 ona first end (upper end in FIG. 1) and a side surface 54 on a second end(lower end in FIG. 1) that is opposite to the first end. The first lead10 projects from the side surface 53, and the second leads 20 projectfrom the side surface 54. The two second leads 20 are arranged along theside surface 54 of the encapsulation resin 50.

The first lead 10 includes an element mount 11 (die pad) having the formof a rectangular plate and a connection portion 12 extending from thedie pad 11. The semiconductor element 30 is mounted on the upper surfaceof the die pad 11. The connection portion 12 has a distal part (upperend in FIG. 1) projecting from the encapsulation resin 50. The partprojecting from the encapsulation resin 50 is an external connectionportion 13 having a distal surface, to which solder adheres when thesemiconductor device 1 is connected to the circuit board. The first lead10 of the present embodiment includes tie bars 14 extending from the diepad 11. Each tie bar 14 has a distal end projecting from a side surfaceof the encapsulation resin 50.

Each second lead 20 is shaped as a rectangular plate. The second lead 20includes an internal connection portion 21 covered with theencapsulation resin 50 and an external connection portion 22 projectingfrom the encapsulation resin 50. The internal connection portion 21 isconnected to the semiconductor element 30 by the clip 40, which isdescribed above. In the same manner as the external connection portion13 of the first lead 10, the external connection portion 22 has a distalsurface to which solder adheres when the semiconductor device 1 isconnected to the circuit board.

As shown in FIGS. 1, 3, and 4, the external connection portion 13 of thefirst lead 10 has the form of a rectangular plate extending along theside surface 53 of the encapsulation resin 50. The external connectionportion 13 includes recesses 13 b and 13 d extending toward theencapsulation resin 50. The recesses 13 b and 13 d are arranged toward acenter from opposite ends of the external connection portion 13 in awidth-wise direction that extends along the side surface 53 of theencapsulation resin 50. Because of the recesses 13 b and 13 d, theexternal connection portion 13 includes end connection parts 13 a and 13e located at opposite ends in the width-wise direction, the recesses 13b and 13 d located toward the center from the end connection parts 13 aand 13 e, and a center connection part 13 c located between the recesses13 b and 13 d. It is preferred that the widths of the end connectionparts 13 a and 13 e be less than half (½) of the width of the centerconnection part 13 c. It is preferred that the depths (dimensions fromthe distal end of the external connection portion 13 toward theencapsulation resin 50) of the recesses 13 b and 13 d be approximatelyhalf (approximately ½) of the dimension of the external connectionportion 13 (dimension from the encapsulation resin 50 toward the distalend of the external connection portion 13).

As shown in FIGS. 1 and 3, in the same manner as the first lead 10, theexternal connection portion 22 of each second lead 20 includes endconnection parts 22 a and 22 e, recesses 22 b and 22 d, and a centerconnection part 22 c.

The entire surface of the first lead 10 is substantially covered with aplating layer. Also, the entire surface of the second leads 20 issubstantially covered with a plating layer. The first lead 10 and thesecond leads 20 are obtained by integrally plating a lead frame 100(refer to FIG. 9), which will be described later, and cutting the leadframe 100. The plating layer covers surfaces excluding cut surfaces andsurfaces covered with a plating mask. The cut surfaces are, for example,an end surface of each of the end connection parts 13 a and 13 e of thefirst lead 10, an end surface of each tie bar 14, and the end connectionparts 22 a and 22 e of the second leads 20. In the present embodiment,the plating layer is formed on a side surface of each of the recesses 13b and 13 d and a side surface of the center connection part 13 c of thefirst lead 10 and a side surface of each of the recesses 22 b and 22 dand a side surface of the center connection part 22 c of each secondlead 20. In the present embodiment, the end surfaces of the endconnection parts 13 a, 13 e, 22 a, and 22 e and the tie bars 14 may bepartially covered with a plating layer by a cutting process.

The material of the first lead 10 and the second leads 20 may be aconductive metal, for example, copper (Cu), a Cu alloy, nickel (Ni), aNi alloy, or Alloy 42. The material of the plating layer may be, forexample, silver (Ag), nickel (Ni), tin (Sn), or an alloy includingthese. Multiple plating layers may be used.

The internal structure of the semiconductor device 1 will now bedescribed.

As shown in FIG. 5, the die pad 11 of the first lead 10 includes a base11 a and flanges 11 b located at opposite sides (left and right sides inFIG. 5) of the base 11 a. In FIG. 5, for the sake of clarity, hatchinglines are given to the flanges 11 b. The flanges 11 b are thinner thanthe base 11 a. The upper surfaces of the flanges 11 b are substantiallyflush with the upper surface of the base 11 a. Thus, the flanges 11 bare not exposed from the lower surface 52 of the encapsulation resin 50.More specifically, the encapsulation resin 50 embeds the flanges 11 b.This limits separation of the first lead 10 from the encapsulation resin50. In FIG. 5, the encapsulation resin 50 is indicated by imaginarylines (double-dashed lines). The same indication is used in the drawingsdescribed below.

The internal connection portion 21 of each second lead 20 includes abase 21 a and flanges 21 b located at opposite sides (left and rightsides in FIG. 5) of the base 21 a. In FIG. 5, for the sake of clarity,hatching lines are given to the flanges 21 b. In the same manner as theflanges 11 b of the die pad 11 of the first lead 10, the flanges 21 bare thinner than the base 21 a. Thus, the encapsulation resin 50 embedsthe flanges 21 b. This limits separation of the second leads 20 from theencapsulation resin 50.

As shown in FIGS. 5 and 6, each second lead 20 includes a connectionrecess 23 used as a restriction portion. The connection recess 23 isobtained by recessing the upper surface of the internal connectionportion 21 of the second lead 20. As shown in FIG. 6, in the presentembodiment, the connection recess 23 is open at the side opposed to thedie pad 11 of the first lead 10. As shown in FIG. 5, the connectionrecess 23 of the second lead 20 is defined by a first restrictionsurface 23 a facing the die pad 11 of the first lead 10 and secondrestriction surfaces 23 b and 23 c opposed to each other in a directionparallel to the first restriction surface 23 a.

As shown in FIGS. 5 and 6, the clip 40 is a connection plate obtained bybending a conductive plate. The clip 40 includes an element connector 41connected to the semiconductor element 30, lead connectors 42 connectedto the respective second leads 20, and a joint 43 joining the elementconnector 41 and the lead connectors 42.

In the present embodiment, the semiconductor device 1 includes the twosecond leads 20. Thus, the clip 40 includes two lead connectors 42corresponding to the two second leads 20. The joint 43 joins the oneelement connector 41 and the two lead connectors 42. In the presentembodiment, the clip 40 includes two tie bars 44 extending from thejoint 43.

As shown in FIG. 8, the element connector 41 is connected to anelectrode 31 of the semiconductor element 30 by solder 72. The elementconnector 41 is rectangular. The element connector 41 includesprojections 41 a. The element connector 41 may include at least oneprojection 41 a.

The projections 41 a are protrusions extending in the width-wisedirection (sideward direction in FIG. 5) of the element connector 41. Asshown in FIG. 8, the projections 41 a define gaps between the elementconnector 41 and the semiconductor element 30. The solder 72 is appliedbetween the element connector 41 and the semiconductor element 30 tofill the gaps so that the element connector 41 and the semiconductorelement 30 are connected to each other by the solder 72.

As shown in FIGS. 5, 6, and 7, the lead connectors 42 of the clip 40 arearranged in the connection recesses 23 of the second leads 20. Each leadconnector 42 is shaped as a rectangular plate. The lead connector 42 isopposed to the first restriction surface 23 a and the second restrictionsurfaces 23 b and 23 c defining the corresponding one of the connectionrecesses 23. As shown in FIGS. 6 and 7, the lead connectors 42 areconnected to the connection recesses 23 by solder 73.

The material of the clip 40 may be, for example, Cu, aluminum (Al), a Cualloy, or an Al alloy. In the same manner as the first lead 10 and thesecond leads 20, the entire surface of the clip 40 is substantiallycovered with a plating layer. The material of the plating layer may be,for example, silver (Ag), nickel (Ni), tin (Sn), or an alloy containingthese. Multiple plating layers may be used. In the same manner as thefirst lead 10 and the second leads 20, portions that are not coveredwith a plating layer are cut surfaces (entire or partial) that areobtained when the lead frame is cut.

The steps of producing the semiconductor device 1 of the presentembodiment will now be described.

In the description of the producing steps, the same reference charactersare given to those elements that ultimately become the correspondingmembers that are described above.

As shown in FIG. 9, the lead frame 100 includes a frame portion 101 andthe first lead 10 and the second leads 20 supported by the frame portion101. The base material of the lead frame 100 includes, for example,copper (Cu).

The lead frame 100 is formed by machining a metal plate (copper plate)having a predetermined thickness. The metal plate is, for example,punched so that through holes 102, 103, and 104 are formed in the metalplate to form the frame portion 101, the first lead 10, the second leads20. Then, for example, pressing is performed so that the flanges 11 band 21 b are formed in the die pad 11 of the first lead 10 and theinternal connection portions 21 of the second leads 20. Additionally,for example, pressing is performed so that the connection recesses 23are formed in the internal connection portions 21 of the second leads20. In FIG. 9, oblique hatching lines are used for clarity of the leadframe 100. Also, discrete dot hatching is used for clarity of theflanges 11 b and 21 b.

The die pad 11 of the first lead 10 is connected to the frame portion101 via a frame connector 111 and tie bars 112. The external connectionportion 13 of the first lead 10 is obtained by cutting the frameconnector 111 along a cutting line L1. The tie bars 14 of the first lead10 are obtained by cutting the tie bars 112 along cutting lines L2. Theinternal connection portions 21 of the second leads 20 are connected tothe frame portion 101 via frame connectors 113. The external connectionportions 22 of the second leads 20 are obtained by cutting the frameconnectors 113 along a cutting line L3.

A through hole 120 extends through the frame connector 111. The throughhole 120 is formed by, for example, a punching process. The through hole120 includes a first through hole 121 extending in the width-wisedirection of the frame connector 111 (direction along the cutting lineL1) and second through holes 122 extending from opposite ends of thefirst through hole 121 toward the die pad 11. The first through hole 121is formed so that the portion between the two second through holes 122will not be cut by cutting along the cutting line L1. The cutting alongthe cutting line L1 across the through hole 120 obtains the externalconnection portion 13 of the first lead 10. More specifically, the firstthrough hole 121 and the second through holes 122 define the centerconnection part 13 c and the recesses 13 b and 13 d, which are shown,for example, in FIG. 1.

In the same manner, a through hole 130 extends through each frameconnector 113. The through hole 120 includes a first through hole 131extending in the width-wise direction of the frame connector 113(direction along the cutting line L3) and second through holes 132extending from opposite ends of the first through hole 131 toward theinternal connection portion 21. The first through hole 131 is formed sothat the portion between the two second through holes 132 will not becut by cutting along the cutting line L3. The cutting along the cuttingline L3 across the through hole 130 obtains the external connectionportion 22 of the second lead 20. More specifically, the first throughhole 131 and the second through holes 132 define the center connectionpart 22 c and the recesses 22 b and 22 d, which are shown in, forexample, FIG. 1.

A plating layer is formed on the entire surface of the lead frame 100 bya plating process. More specifically, the platting layer is formed onthe side surfaces of the through holes 120 and 130. Thus, the platinglayer is formed on the recesses 13 b and 13 d and the center connectionpart 13 c of the external connection portion 13 of the first lead 10 andthe recesses 22 b and 22 d and the center connection part 22 c of theexternal connection portion 22 of each second lead 20.

FIG. 10 shows a lead frame 200 including a frame portion 201 and theclip 40 supported by the frame portion 201. The base material of thelead frame 200 includes, for example, copper (Cu). The clip 40 isconnected to the frame portion 201 via tie bars 202.

The lead frame 200 is formed by machining a metal plate (copper plate)having a predetermined thickness. The metal plate is, for example,punched so that through holes 203 and 204 are formed in the metal plateto form the frame portion 201, the tie bars 202, and the clip 40. Then,for example, pressing is performed to form the element connector 41, thelead connectors 42, and the joint 43 of the clip 40. A plating layer isformed on the entire surface of the lead frame 200 by a plating process.In the lead frame 200, the tie bars 202 are cut along cutting lines L4by a cutting process to separate the clip 40.

The lead frame 100, shown in FIG. 9, is connected to the semiconductorelement 30 and the clip 40, shown in FIG. 5. Then, the encapsulationresin 50 (indicated by double-dashed lines) is formed in molds.

The frame connectors 111 and 113 and the tie bars 112 are cut by cuttingalong the cutting lines L1 to L3 to separate the semiconductor device 1.

FIG. 9 shows the lead frame 100 that is located in a region includingthe first lead 10 and the second leads 20 of a single semiconductordevice. FIG. 10 shows the lead frame 200 that is located in a regionincluding the clip 40 for a single semiconductor device. The lead frames100 and 200 in these regions are arranged, for example, in a matrix, andmultiple semiconductor devices 1 (first leads 10, second leads 20, clips40, and encapsulation resins 50) are simultaneously formed.

Operation

The operation of the semiconductor device 1 will now be described.

A first referential example and a second referential example in relationto the present embodiment will now be described. In the description ofthe first referential example and the second referential example, thesame reference characters are given to those members that are the sameas the corresponding members of the semiconductor device 1.

FIG. 11 shows a portion of the first referential example of asemiconductor device 80.

The semiconductor device 80 shown in FIG. 11 includes a lead 81 havingan end surface 81 a, which is a cut surface that is cut through in thewidth-wise direction.

As shown in FIG. 14, the semiconductor device 80 is mounted on a circuitboard 300. The lead 81 of the semiconductor device 80 is connected to apad 301 of the circuit board 300 by solder 302. In the case of the lead81, the solder 302 has a low wettability to the end surface 81 a, or thecut surface. Thus, the amount of the solder 302 adhered to the endsurface 81 a may be insufficient as compared to an amount needed to fixthe semiconductor device 80. This lowers the mount strength. When thelead 81 is cut, the end surface 81 a may be slightly covered with aplating layer from the surface of the lead 81 depending on the cuttingdirection of the lead 81. The solder 302 may adhere to the platinglayer. However, the plating layer is so limited that the solder 302 isstill insufficient and the mount strength is lowered.

FIG. 12 shows a portion of the second referential example of asemiconductor device 90.

The semiconductor device 90 shown in FIG. 12 includes a lead 91 thatincludes connection portions 92 located at opposite ends in thewidth-wise direction and a recess 93 located between the connectionportions 92. The lead 91 is obtained by forming a through hole thatextends through a part connected to the frame portion of the lead framein the width-wise direction and cutting the part across the throughhole. Because of the through hole, a plating layer is formed on a sidesurface of the recess 93. Thus, the wettability of solder is higher thanthat in the semiconductor device 80 shown in FIG. 11. However, when theencapsulation resin 50 is formed, a resin burr 55 is formed. When theencapsulation resin 50 is molded, the resin burr 55 is formed in a gapbetween a mold and the lead 91. A molten resin has properties that tendto flow to a center of the surface of the lead 91 in the width-wisedirection of the lead 91 and relatively do not tend to flow to ends ofthe lead 91 in the width-wise direction. Thus, the resin burr 55 islikely to largely spread in the vicinity of the center of the lead 91.The resin burr 55 may partially cover the side surface of the recess 93.As a result, as shown in FIG. 15, when the semiconductor device 90 ismounted on the circuit board 300, the amount of the solder 302 adheredto the side surface of the recess 93 of the lead 91 may be insufficientas compared to an amount needed to fix the semiconductor device 90. Thislowers the mount strength.

FIG. 13 shows a portion of the semiconductor device 1 of the presentembodiment.

In the semiconductor device 1 shown in FIG. 13, the first lead 10includes the recesses 13 b and 13 d at positions toward the center fromopposite ends in the width-wise direction. Because of the recesses 13 band 13 d, the external connection portion 13 includes the end connectionparts 13 a and 13 e located at opposite ends in the width-wisedirection, the recesses 13 b and 13 d located toward the center from theend connection parts 13 a and 13 e, and the center connection part 13 clocated between the recesses 13 b and 13 d.

As described above, the widths of the end connection parts 13 a and 13 eare less than half (½) of the width of the center connection part 13 c.With such a configuration, in which the center connection part 13 c hasa greater width and the recesses 13 b and 13 d are arranged at oppositeends of the external connection portion 13, when the encapsulation resin50 is formed, the resin burr 55 remains on the upper surface of thecenter connection part 13 c and will not easily cover the side surfaceof the center connection part 13 c. Additionally, the depths of therecesses 13 b and 13 d are approximately half of the dimension of theexternal connection portion 13. If the recesses 13 b and 13 d are toodeep, the resin burr 55 is readily formed. If the recesses 13 b and 13 dare too shallow, the wettability of solder may be lowered. Therefore,sufficient solder adheres to the external connection portion 13 (centerconnection part 13 c and recesses 13 b and 13 d) when mounted on thecircuit board. This increases the soldering strength and improves thestrength of mounting on the circuit board.

In the external connection portion 13, the plating layer is formed onthe side surfaces of the recesses 13 b and 13 d and the side surface ofthe center connection part 13 c. Thus, the wettability of solder issatisfactory. Thus, as shown in FIGS. 16A and 16B, when thesemiconductor device 1 is mounted on the circuit board 300, the solder302 sufficiently adheres to the external connection portion 13 (centerconnection part 13 c and recesses 13 b and 13 d). This increases thestrength of soldering on the pad 301 of the circuit board 300 andimproves the strength of mounting on the circuit board 300. Further, asshown in FIGS. 17A and 17B, when the amount of the solder 302 isincreased, the solder 302 adheres to front surfaces of the endconnection parts 13 a and 13 e of the external connection portion 13.This further improves the strength of mounting on the circuit board 300.

The external connection portions 22 of the second leads 20 are formed inthe same manner as the external connection portion 13 of the first lead10. Thus, in the second leads 20, the strength of mounting on thecircuit board is improved in the same manner as the first lead 10.

As shown in FIGS. 5 and 6, the lead connectors 42 of the clip 40 arearranged in the connection recesses 23 of the second leads 20. Each leadconnector 42 is shaped as a rectangular plate. The lead connector 42 isopposed to the first restriction surface 23 a and the second restrictionsurfaces 23 b and 23 c defining the connection recess 23. The leadconnectors 42 are connected to the connection recesses 23 by the solder73.

The solder 73 is molten in a reflow process. The lead connectors 42 arearranged in the connection recesses 23 of the second leads 20. Thus,when the solder 73 is molten, the second restriction surfaces 23 b and23 c of the connection recesses 23 restrict movement of the leadconnectors 42 (movement in a direction in which the second leads 20 arearranged or in a direction orthogonal to the second restriction surfaces23 b and 23 c). This limits misalignment of the lead connectors 42relative to the connection recesses 23, that is, displacement in adirection the second leads 20 are arranged (sideward direction in FIG.5).

During soldering, the lead connectors 42 are moved toward the firstrestriction surfaces 23 a by surface tension of the molten solder 73.The first restriction surfaces 23 a restrict the movement of the leadconnectors 42 (movement in a direction from the first lead 10 toward thesecond leads 20) caused by the molten solder 73. This limitsmisalignment of the lead connectors 42 relative to the connectionrecesses 23, that is, displacement in a direction orthogonal to thefirst restriction surfaces (vertical direction in FIG. 5).

The semiconductor device 1 includes the two second leads 20, and theelectrode 31 arranged on the upper surface of the semiconductor element30 is connected to the two second leads 20 by the clip 40. Thus,inclination of the clip 40 is limited. The inclination of the clip 40may result in displacement of the element connector 41, that is,misalignment of the semiconductor element 30 relative to the elementconnector 41. In this regard, the two second leads 20 are provided, andthe two second leads 20 are connected to the lead connectors 42 of theclip 40 to limit misalignment of the semiconductor element 30 with theelement connector 41.

The lead connectors 42 of the clip 40 are each rectangular. Theconnection recess 23 of each second lead 20 is defined by the firstrestriction surface 23 a and the second restriction surfaces 23 b and 23c. The first restriction surface 23 a is orthogonal to the secondrestriction surfaces 23 b and 23 c. The surface tension of the moltensolder 73 allows each side of the lead connectors 42 to be arrangedsubstantially parallel to the first restriction surface 23 a and thesecond restriction surfaces 23 b and 23 c of the respective connectionrecesses 23. This limits inclination of the clip 40 relative to thesecond leads 20.

The semiconductor device 1 includes the two second leads 20, and theelectrode 31 arranged on the upper surface of the semiconductor element30 is connected to the two second leads 20 by the clip 40. Thus, onlyone of the two second leads 20 may be connected to a wire of the circuitboard. This increases the degree of freedom for designing the circuitboard.

As described above, the present embodiment has the advantages describedbelow.

(1) The external connection portion 13 of the first lead 10 includes therecesses 13 b and 13 d in positions toward the center from opposite endsin the width-wise direction. Because of the recesses 13 b and 13 d, theexternal connection portion 13 includes the end connection parts 13 aand 13 e located at opposite ends in the width-wise direction, therecesses 13 b and 13 d located toward the center from the end connectionparts 13 a and 13 e, and the center connection part 13 c located betweenthe recesses 13 b and 13 d. When the encapsulation resin 50 is formed,the resin burr 55 remains on the upper surface of the center connectionpart 13 c and will not cover the side surface of the center connectionpart 13 c. Thus, when mounting on the circuit board, sufficient solderadheres to the external connection portion 13 (center connection part 13c and recesses 13 b and 13 d). This increases the soldering strength andimproves the strength of mounting on the circuit board.

The external connection portions 22 of the second leads 20 are formed inthe same manner as the external connection portion 13 of the first lead10. Thus, in the second leads 20, the strength of mounting on thecircuit board is improved in the same manner as the first lead 10.

(2) The plating layer is formed on the side surfaces of the recesses 13b and 13 d and the side surface of the center connection part 13 c.Thus, the wettability of solder is satisfactory. Thus, when mounting onthe circuit board, sufficient solder adheres to the external connectionportion 13 (center connection part 13 c and recesses 13 b and 13 d).This increases the soldering strength and improves the strength ofmounting on the circuit board.

The external connection portions 22 of the second leads 20 are formed inthe same manner as the external connection portion 13 of the first lead10. Thus, in the second leads 20, the strength of mounting on thecircuit board is improved in the same manner as the first lead 10.

(3) Each second lead 20 includes the connection recess 23, and theconnection recess 23 is defined by the first restriction surface 23 aand the second restriction surfaces that are orthogonal to the firstrestriction surface 23 a. The lead connectors 42 of the clip 40 areconnected to the connection recesses 23 by the solder 73. The firstrestriction surfaces 23 a and the second restriction surfaces 23 b and23 c of the connection recesses 23 restrict movement of the leadconnectors 42 in directions corresponding to each surface. Thus,misalignment of the clip 40 relative to the second leads 20 is limited.The misalignment of the clip 40 may result in misalignment of theelement connector 41 of the clip 40 with the semiconductor element 30.Thus, misalignment of the semiconductor element 30 relative to theelement connector 41 of the clip 40 is limited. This obtains stableelectrical connection between the semiconductor element 30 and thesecond leads 20.

Modified Examples

The embodiment may be modified as follows.

The semiconductor device 1 of the present embodiment includes the twosecond leads 20, and each of the two second leads 20 includes theconnection recess 23. Thus, the semiconductor device 1 of the presentembodiment includes two pairs of second restriction surfaces 23 b and 23c. Instead, one pair of second restriction surfaces 23 b and 23 c may beused. For example, in FIG. 5, the second restriction surface 23 b (orsecond restriction surface 23 c) is omitted from the left one of thesecond leads 20, and the second restriction surface 23 c (or secondrestriction surface 23 b) is omitted from the right one of the secondleads 20. Alternatively, in FIG. 5, the second restriction surfaces 23 band 23 c are omitted from the left one (right one) of the second leads20. Even with such configurations, movement of the clip 40 isrestricted.

In the embodiment, the shape of the clip 40 may be changed.

As shown in FIG. 18, a semiconductor device 1 a includes a clip 40 athat is bent so that the lead connector 42 has an end surface 42 acontacting the connection recess 23 of the second lead 20. The end ofthe lead connector 42 is connected to the connection recess 23 of thesecond lead 20 by solder. In this case, the connection recess 23 of thesecond lead 20 may be open toward the first lead 10 in the same manneras in the embodiment or may be closed toward the first lead 10.

As shown in FIG. 19, a semiconductor device 1 b includes a clip 40 b inwhich the lead connector 42 includes an end portion 42 b located closerto the external connection portion 22 than the connection recess 23 ofthe second lead 20. In the clip 40 b, the lead connector 42 includes aportion 42 c located closer to the element connector 41 than the endportion 42 b, and the portion 42 c is connected to the connection recess23 of the second lead 20 by solder.

In the embodiment, the number of second leads 20 may be changed.

As shown in FIG. 20, a semiconductor device 1 c includes a single firstlead 10 and a single second lead 20. A clip 40 c includes an elementconnector 41 at one end, a lead connector 42 at the other end, and thejoint 43 between the element connector 41 and the lead connector 42.

As shown in FIG. 21, in a semiconductor device 1 d, the width of thesecond lead 20 may be changed. Also, the width of the lead connector 42of a clip 40 d may be set in accordance with the width of the secondlead 20.

In the embodiment, a semiconductor device may include a semiconductorelement having an upper surface including two or more electrodes. Thesemiconductor device includes two or more second leads in accordancewith the electrodes of the semiconductor element.

FIG. 22 shows a semiconductor device 1 e in which a semiconductorelement 30 e has an upper surface including two electrodes 31 a and 31 band is mounted on the die pad 11. The semiconductor element 30 e is, forexample, a transistor. The electrode 31 a is connected to a second lead20 a via a first connection plate 45 a (clip), and the electrode 31 b isconnected to a second lead 20 b via a second connection plate 45 b(clip). The semiconductor element may be, for example, a diode having anupper surface including an anode electrode and a cathode electrode.

In the embodiment, the shapes of the external connection portions 13 and22 may be changed.

As shown in FIG. 23, in the external connection portion 13, the endconnection parts 13 a and 13 e may project more than the end surface ofthe center connection part 13 c. As shown in FIG. 24, in a process ofcutting the frame connector 111 along the cutting line L1, the frameconnector 111 is cut so that the end connection parts 13 a and 13 eproject more than the end surface of the center connection part 13 c.The amount of the end connection parts 13 a and 13 e projecting from theend surface of the center connection part 13 c may be changed byadjusting the position of the cutting line L1.

In the same manner, as shown in FIG. 23, in the external connectionportion 22, the end connection parts 22 a and 22 e may project more thanthe end surface of the center connection part 22 c. As shown in FIG. 24,in a process of cutting the frame connectors 113 along the cutting lineL3, the frame connectors 113 are cut so that the end connection parts 22a and 22 e project from the end surface of the center connection part 22c. The amount of the end connection parts 22 a and 22 e projecting fromthe end surface of the center connection part 22 c may be changed byadjusting the position of the cutting line L3.

In the embodiment, the semiconductor element 30 and the second leads 20are connected by the clip 40 (connection plate). Instead, a wire may beused for connection. When a wire is used, the wire may be connected tothe connection recesses 23 of the second leads 20. The connectionrecesses 23 may be omitted from the second leads 20.

What is claimed is:
 1. A semiconductor device, comprising: asemiconductor element; leads; and an encapsulation resin covering aportion of each of the leads and the semiconductor element, wherein eachof the leads includes an external connection portion projecting from aside surface of the encapsulation resin, the external connection portionof at least one of the leads has opposite ends in a width-wise directionthat extends along the side surface of the encapsulation resin, theexternal connection portion includes two recesses arranged toward acenter in the width-wise direction from the opposite ends, the tworecesses extend from a distal surface of the external connection portiontoward the encapsulation resin, the opposite ends in the width-wisedirection define an end connection part, the external connection portionincludes a part between the two recesses defining a center connectionpart, and an entire portion of each of the recesses is exposed from theencapsulation resin.
 2. The semiconductor device according to claim 1,wherein at least a portion of an end surface of the end connection partis free of a plating layer.
 3. The semiconductor device according toclaim 1, wherein the end connection part projects more than an endsurface of the center connection part.
 4. The semiconductor deviceaccording to claim 1, wherein each of the recesses has a depth from thedistal surface to a bottom in a direction from the distal surface of theexternal connection portion toward the encapsulation resin, and thedepth of each of the recesses is shorter than a length of the externalconnection portion from the distal surface of the external connectionportion to the encapsulation resin.
 5. A semiconductor device,comprising: a semiconductor element; leads; and an encapsulation resincovering a portion of each of the leads and the semiconductor element,wherein each of the leads includes an external connection portionprojecting from a side surface of the encapsulation resin, the externalconnection portion of at least one of the leads has opposite ends in awidth-wise direction that extends along the side surface of theencapsulation resin, the external connection portion includes tworecesses arranged toward a center in the width-wise direction from theopposite ends, the two recesses extend from a distal surface of theexternal connection portion toward the encapsulation resin, the oppositeends in the width-wise direction define an end connection part, theexternal connection portion includes a part between the two recessesdefining a center connection part, and the semiconductor device furthercomprises a plating layer covering a wall surface of the recesses and anend surface of the center connection part.
 6. A method for producing asemiconductor device that encapsulates a semiconductor element and aportion of each of leads with a resin, the method comprising steps of:preparing a lead frame that form the leads; forming an encapsulationresin covering a portion of each of the leads and a semiconductorelement mounted on the lead frame; and forming an external connectionportion that projects from a side surface of the encapsulation resin bycutting the leads, wherein the leads are connected to a frame portion ofthe lead frame by a frame connector that forms the external connectionportion, the frame connector includes a first through hole extending ina width-wise direction and second through holes extending from oppositeends of the first through hole away from the frame portion, and in theforming an external connection portion, the frame connector is cutacross the first through hole so that the external connection portion isformed to have opposite ends in a width-wise direction that extendsalong a side surface of the encapsulation resin and include tworecesses, the two recesses being arranged toward a center in thewidth-wise direction from the opposite ends and extending from a distalsurface of the external connection portion toward the encapsulationresin, the opposite ends of the external connection portion in thewidth-wise direction define an end connection part, and the externalconnection portion includes a part between the two recesses defining acenter connection part.
 7. The method according to claim 6, wherein aplating layer is formed on a surface of the lead frame including thefirst through hole and the second through holes.
 8. The method accordingto claim 6, wherein in the forming an external connection portion, theexternal connection portion is cut so that the end connection partprojects more than an end surface of the center connection part.
 9. Asemiconductor device, comprising: a first lead including a die pad andan external connection portion; a second lead including an internalconnection portion and an external connection portion; a semiconductorelement mounted on the die pad; and a connection plate electricallyconnecting the semiconductor element and the second lead, wherein theconnection plate includes an element connector connected to thesemiconductor element, a lead connector connected to the second lead,and a joint joining the element connector and the lead connector, thesecond lead includes a restriction portion connected to the leadconnector and including restriction surfaces, and the restrictionportion restricts movement of the connection plate with the restrictionsurfaces.
 10. The semiconductor device according to claim 9, wherein therestriction surfaces include a first restriction surface opposed to thelead connector and a second restriction surface opposed to the leadconnector and orthogonal to the first restriction surface.
 11. Thesemiconductor device according to claim 10, wherein the firstrestriction surface faces toward the die pad.
 12. The semiconductordevice according to claim 10, wherein the second restriction surface isone of two second restriction surfaces opposed to each other, and therestriction portion includes the two second restriction surfaces. 13.The semiconductor device according to claim 9, wherein the restrictionportion is a connection recess arranged in an upper surface of thesecond lead.
 14. The semiconductor device according to claim 13, whereinthe connection recess is open toward the first lead.
 15. Thesemiconductor device according to claim 9, further comprising anencapsulation resin covering the die pad, the internal connectionportion, the semiconductor element, and the connection plate.
 16. Thesemiconductor device according to claim 15, wherein the first lead andthe second lead are exposed from a lower surface of the encapsulationresin.
 17. The semiconductor device according to claim 15, wherein thesecond lead is one of second leads, and the second leads are arrangedalong a side surface of the encapsulation resin.
 18. The semiconductordevice according to claim 9, wherein a semiconductor element is mountedon the die pad, the die pad is tetragonal, the second lead is one of twosecond leads, the two second leads are arranged along a side of the diepad opposite to a side of the external connection portion, the leadconnector is one of two lead connectors, the connection plate includesthe element connector connected to the semiconductor element and the twolead connectors respectively connected to the two second leads, and thejoint joins the element connector and the two lead connectors.
 19. Thesemiconductor device according to claim 9, wherein a semiconductorelement having an upper surface including two electrodes is mounted onthe die pad, the die pad is tetragonal, the second lead is one of twosecond leads, the two second leads are arranged along a side of the diepad opposite to a side of the external connection portion, and theconnection plate includes a first connection plate connecting one of thetwo electrodes of the semiconductor element and one of the two secondleads and a second connection plate connecting the other one of the twoelectrodes of the semiconductor element and the other one of the twosecond leads.
 20. The semiconductor device according to claim 9, whereinthe external connection portion of the first lead and the externalconnection portion of the second lead include an external connectionportion projecting from a side surface of an encapsulation resin, theexternal connection portion of at least one of the first lead and thesecond lead has opposite ends in a width-wise direction that extendsalong the side surface of the encapsulation resin, the externalconnection portion includes two recesses arranged toward a center in thewidth-wise direction from the opposite ends, the two recesses extendfrom a distal surface of the external connection portion toward theencapsulation resin, the opposite ends in the width-wise directiondefine an end connection part, and the external connection portionincludes a part between the two recesses defining a center connectionpart.
 21. The semiconductor device according to claim 20, furthercomprising a plating layer covering a wall surface of the recesses andan end surface of the center connection part.
 22. The semiconductordevice according to claim 20, wherein at least a portion of an endsurface of the end connection part is free of a plating layer.
 23. Thesemiconductor device according to claim 20, wherein the end connectionpart projects more than an end surface of the center connection part.